How two Australian sisters channeled their love of STEM and coral reefs into the most glorious participatory art project.

“We’re used to thinking about math as something you have to learn through textbooks and equations,” says science writer Margaret Wertheim. But through their Institute for Figuring, she and her sister, Christine, have made it their mission to help people see math and science differently by finding hands-on ways to engage them with abstract concepts. Among their efforts: the mesmerizing Crochet Coral Reef. Why crochet and coral? Many reef organisms are living examples of a complicated form of geometry, and crocheting their shapes allows people to work with geometric principles in a tactile way.

Started in 2007, the Wertheims’ reef grew out of the Australian sisters’ many interests: their passion for math and science; shared fondness for crochet; love of their country’s Great Barrier Reef and desire to highlight global warming’s impact on coral reefs and oceans in general. Today the Crochet Coral Reef is made up of thousands of handcrafted corals and reef organisms — created by a network of contributors — that Margaret and Christine, an artist and professor, have curated into displays that have been exhibited worldwide. Here, Margaret Wertheim shares some of the amazing organisms created for their project and shows how their crocheted reef has grown and evolved over the years.

Math like you’ve never seen it before

Many reef organisms, like nudibranches, sponges and kelps, possess structures that embody a head-scratching form of geometry called hyperbolic geometry. Hyperbolic geometry was discovered in the 19th century, revolutionizing the field of mathematics and eventually paving the way for Einstein’s general theory of relativity. Yet physical and durable hyperbolic models that would allow people to explore hyperbolic geometry in a tactile way did not exist until 1997 when Dr. Daina Taimina, a mathematician at Cornell, realized forms could be made using crochet. To create this 18-inch-long hyperbolic shape, artist Siew Chu Kerk followed Taimina’s formula pretty exactly, says Wertheim, “which is crochet n stitches, increase one and then repeat that ad infinitum.”

They’re more than hyperbolic The Wertheim sisters first called their project the Hyperbolic Crochet Coral Reef, but they quickly realized that in order to capture the full beauty of this special ecosystem, they’d need to include organisms that lacked hyperbolic features. Some reef creatures have only a few hyperbolic parts (and some display no hyperbolic geometry at all). For example, the curlicues at the end of this octopus-like creature’s tentacles and its center are hyperbolic shapes, Wertheim says, but other elements of this organism, like the long parts of the tentacles, are not. Helen Bernasconi, an early contributor to the project and a rug weaver by trade, sheared, spun and dyed wool from her own sheep to make this piece.

Bringing art into the equation

While this delightful pastel creation, made by Vonda N. McIntyre, is a crocheted replica of fingerling coral, not all contributors hew so closely to reality. This was a deliberate artistic choice on the part of the Wertheim sisters. “Just as a painter is painting a landscape and doesn’t want to produce a photocopy of it, we want to be like Van Gogh, Cézanne or Monet,” says Wertheim. “We’re trying to look at the world and produce a beautiful aesthetic version.”

A branching network of makers

This kelp piece shows the technical skill of Ildiko Szabo, a theater costume designer and another of the project’s earliest contributors. After she and Christine came up with the idea of such a reef, Wertheim recalls, “I put something up on [the Institute of Figuring’s] website saying: Is there anyone else who’d like to join us in this quixotic project at the intersection of handicraft, mathematics and environmentalism?” To their surprise and delight, they began receiving crocheted objects in the mail from people they’d never met. Years later, Szabo remains one of the reef’s 40 to 50 core contributors. Altogether, nearly 100 people — whose ranks include sci-fi writers and computer programmers — are behind the roughly 10,000 pieces that make up the reef.

Small pieces, major work

Rebecca Peapples created this beaded piece (which is attached to the center of the white star in the next photo) using a traditional beading stitch called the herringbone. While only around three inches in length, Wertheim estimates that Peapples spent around 10 to 15 hours to produce it (pieces in the reef range in size from a few inches to a few feet). The white star, about the size of a human hand, probably took up to 30 hours to make; some pieces have taken hundreds of hours. “One reason why I think the reef is powerful is because everybody can tell when they walk in the door there has been a huge commitment of time,” she says.